Microsoft Update KB4549951 deleted my files! HELP!

Hi Seattle4718, this is happening much too often at the moment, you are logged into a temporary account . . .

Before you do anything or move any files around
Restart (not shut down) your PC 4 times, each time let your PC get to the Desktop before the next restart, this will fix this issue a lot of the time . ..

Otherwise:

Please open Windows File Explorer
Navigate to C:\Users
Do you see two user folders that look like yours?
Open those folders and check inside Pictures, Documents . . . etc. and see if your files are there

If your files are there:

Create a new user profile with Admin privileges
Log into the new user profile
Copy all your data from the old profile to the new profile (Documents Library, Pictures Library . . . etc.)

If you still have not found your files, look for a Windows.old folder on your C Drive, expand that to open the users folder contained inside - check there for your files, icons . . .etc.

If you do find your files . . . etc. there, copy them out as soon as possible as Windows will remove the Windows.old folder in time

NOTE VERY IMPORTANT: Do Not copy your files into the Temporary profile you are currently in, when the situation is corrected, your files will be deleted with the Temporary Profile and will not be recoverable !!

Thank you so much for your response!    I re-started by computer 4 times (actually 5 as I kept my fingers crossed) and it was not magically fixed.  Strange this is my Documents folders have some folders but are all emty.  The microsoft Pictures folder does have my pictures but all documents and program data files are gone. 

Luckily this morning before the 1st restart after the message about temporary login, I did copy all of my files to an external hard drive. 

I do not have a windows.old file

-I am guessing that I will just copy the files from my external drive back to the c drive under my current user?  Should I create a new one first?

-When I open File Explorer it still shows  short cuts and recent files (tho they are not able to open), how do I clean this up?

-What do I do to keep this from ever happening again.

Thank you, thank you for your help!!  Super scarey as all of my client's financial files etc just apparently went away!  (Thank goodness for googling before 1st restart after update)

If this is happening it's probably because you're either using Known Folder Redirect &/or using an old version of OneDrive. If you're using KFR, you have to keep your files for a particular folder at that folder's redirect destination. If you keep them in the source folder they can get deleted during updates. If you're using an old version of OneDrive, update to the latest build ASAP.